This is a category D study. The only treatment currently available for age-related macular degeneration is one or another form of laser therapy. Laser photocoagulation results in heat-generated selective destruction of areas of the retina, including the neurosensory retina and retinal pigmented epithelium overlying vascular leakage sites. This type of treatment may confine the extent of damage, but rarely improves vision. In advanced disease, large lesions may preclude treatment with standard laser therapy. The goal of photodynamic therapy is to selectively destroy diseased cells with light-activated drugs while minimizing damage to surrounding normal tissue. The objective of this trial is to evaluate the safety and efficacy of two dose levels of tin ethyl etiopurpurin with photodynamic therapy for the treatment of subfoveal choroidal neovascularization in patients with age-related macular degeneration. The efficacy of treatments at each of the two dose levels will be compared to placebo. Assessments will include the degree of stabilization or improvement in visual acuity, the durability of the treatment response, change from baseline in area of serous sensory-retinal detachment and the area of the choroidal neovascularization. Preclinical studies in animals have shown that tin ethyl etiopurpurin is selectively retained in hyperproliferating tissues and that phototherapy with tin ethyl etiopurpurin may be effective in treating diseases associated with hyperproliferation, high vascularity, or neovascular tissues, all criteria that apply to age-related macular degeneration. Phase I trials with the compound in patients with age-related macular degeneration indicated a good initial effect in closure of the neovascular membranes and an increase for stabilization and visual acuity. However, partial or complete recurrence was generally seen in nearly three-quarters of the cases within four months. The current protocol has been designed to further investigate the potential use of photodynamic therapy with tin ethyl etiopurin.